Apatosaurus
Apatosaurus ("deceptive lizard") was a sauropod dinosaur that lived in the Late Jurassic of North America. Due to its association with the now-redundant genus "Brontosaurus", it has become one of the most famous dinosaurs known to the general public. Description The length of Apatosaurus has usually been estimated at around 23 meters.Mazzetta, G.V.; Christiansen, P.; Farina, R.A. (2004). "Giants and bizarres: body size of some southern South American Cretaceous dinosaurs" (PDF). Historical Biology 2004: 1–13. The dinosaur was stockier than many related genera such as Diplodocus, but recent weight estimates have varied between 16Henderson, Donald M. (2006). "Burly Gaits: Centers of mass, stability, and the trackways of sauropod dinosaurs". Journal of Vertebrae Paleontology 26 (4): 907–921. doi:10.1671/0272-4634(2006)26907:BGCOMS2.0.CO;2. and 22Seebacher, Frank (2001). "A new method to calculate allometric length-mass relationships of dinosaurs". Journal of Vertebrate Paleontology 21: 51–52. doi:10.1671/0272-4634(2001)0210051:ANMTCA2.0.CO;2. ISSN 0272-4634. tonnes. Like other sauropods, Apatosaurus had a small head compared to its body, and its mouth was filled with chisel-like teeth. It also possessed a deep chest and very robust bones.Lovelace, David M.; Hartman, Scott A.; and Wahl, William R. (2007). "Morphology of a specimen of Supersaurus (Dinosauria, Sauropoda) from the Morrison Formation of Wyoming, and a re-evaluation of diplodocid phylogeny". Arquivos do Museu Nacional 65 (4): 527–544. the brontosaurus was registered as a different species in 2015, it is slightly different from the apatosaurus. Classification Apatosaurus is part of the taxonomic family Diplodocidae, which also contains the genera Diplodocus, Barosaurus and others.Taylor, M.P. and Naish, D. (2005). "The phylogenetic taxonomy of Diplodocoidea (Dinosauria: Sauropoda)". PaleoBios 25 (2): 1–7. Archived from the original on 2010-01-18. The type specimen, Apatosaurus ajax, was described and named by Othniel Charles Marsh in 1877 after the hero of Greek mythology. There are three other valid species.Carpenter, K. and McIntosh, J. (1994). "Upper Jurassic sauropod babies from the Morrison Formation", In: K. Carpenter, K. F. Hirsch, and J. R. Horner (eds.), Dinosaur Eggs and Babies. Cambridge University Press, Cambridge 265–278 Discovery The first (and incomplete) specimen of Apatosaurus was discovered in 1877 by Othniel Charles Marsh. Two years later, he found another sauropod dinosaur, which because of its tremendous size, he described as a separate genus, Brontosaurus excelus ("thunder lizard"). It was the largest dinosaur to be discovered at the time, and when its skeleton was mounted in public it immediately became one of the most famous dinosaurs. However, in 1903, Elmer Riggs rexamined the skeleton, and found that the mounted specimen was in fact a composite of several different types of sauropod, including a very bulky skull unlike that of similar species. Based on the original remains that were left, Riggs concluded that Brontosaurus should in fact be classified as an Apatosaurus, thus rendering the former as an invalid synonym due to the taxonomic rules of priority.Riggs, Elmer (1903). "Structure and Relationships of Opisthocoelian Dinosaurs. Part I, Apatosaurus Marsh". Publications of the Field Columbian Museum Geological Series (2): 165–196. Changes were quickly made to the skeletons of "Brontosaurus" in museums, and the vast majority of paleontologists support Riggs's classification, with few exceptions.Bakker, R.T. (1998). "Dinosaur mid-life crisis: the Jurassic-Cretaceous transition in Wyoming and Colorado". In: S.G. Lucas, J.I. Kirkland, & J.W. Estep (eds.) Lower and Middle Cretaceous Terrestrial Ecosystems; New Mexico Museum of Natural History and Science Bulletin, 14: 67–77. Paleobiology Apatosaurus has been well-studied, largely due to its association with "Brontosaurus". It was also one of the more common sauropods in its ecosystem.Foster, John (2007). Jurassic West: The Dinosaurs of the Morrison Formation and Their World. Indiana University Press. p. 273. ISBN 978-0-253-34870-8. Posture Apatosaurus and its relatives have long been depicted with swan-like necks. Recent research and computer models suggests that they could not hold their necks far above a horizontal positionStevens, Kent A.; Parrish, JM (1999). "Neck Posture and Feeding Habits of Two Jurassic Sauropod Dinosaurs". Science 284 (5415): 798–800. doi:10.1126/science.284.5415.798. PMID 10221910. Retrieved 2008-08-03., but other studies show that all living types of tetrapod naturally hold their necks up at the maximum possible vertical extension. Based upon this, it has been suggested Apatosaurus held its neck in an upward position, but with its head angled in a resting posture.Taylor, M.P.; Wedel, M.J.; Naish, D. (2009). "Head and neck posture in sauropod dinosaurs inferred from extant animals". Acta Palaeontologica Polonica 54 (2): 213–220. doi:10.4202/app.2009.0007. (Abstract) Footprints of juvenile Apatosaurus were discovered in 2006 that showed only the hind feet left tracks. This suggests that young individuals were able to run on their back legs for a short time, rather like some types of modern-day lizard.Rajewski, Genevieve (May 2008). "Where Dinosaurs Roamed". Smithsonian: 20–24. Archived from the original on 27 April 2008. Retrieved 2008-04-30. Physiology Based on the comparison of tidal volumes of animals, Apatosaurus is believed to have had an avian respiratory system, or something similar.Paladino, F.V., Spotila, J.R., and Dodson, P. (1997). "A Blueprint for Giants: Modeling the Physiology of Large Dinosaurs." In Farlow, J.O. and Brett-Surman, M.K. (eds.), The Complete Dinosaur, Indiana University Press, 491–504. doi0253333490. Microscopic bone study of Apatosaurus has shown that they grew very rapidly, reaching sexual maturity in approximately 10 years or so.Curry, Kristina A. (1999). "Ontogenetic histology of Apatosaurus (Dinosauria: Sauropoda): new insights on growth rates and longevity". Journal of Vertebrate Paleontology 19 (4): 654–665. doi:10.1080/02724634.1999.10011179. JSTOR 4524036. Tail In 1997, a computer scientist from Microsoft published a report on the mechanics of Apatosaurus tails. Using computer models, he was able to suggest that the dinosaur's whip-like tail may actually have been able to produce sounds louder than a cannon when whipped.Zimmer, C. (1997). "Dinosaurs in Motion." Discover, 1 November 1997. DISCOVER Magazine. Retrieved 27 July 2008. In popular culture Main article: Apatosaurus in popular culture Even though the name "Brontosaurus" had been rendered invalid only a couple decades after its discovery, the name continued to persist in the public imagination, which made Apatosaurus one of the most famous dinosaurs in existence.Gould, S.J. (1991). Bully for Brontosaurus: Reflections in Natural History, W. W. Norton & Co., 540pp. One of its earliest appearances in culture was in the silent animated film, Gertie the Dinosaur,Donald Crafton (1982). Before Mickey: The Animated Film 1898-1928. MIT Press. ISBN 0-262-03083-7. in which the title character was based off a skeletal mount in the American Museum of Natural History in New York.http://www.sdnhm.org/exhibits/dinosrr/index.html A green Apatosaurus has also been the logo and mascot of Sinclair Oil for many years.Sinclair Oil Corporation, (2008). Evolution of the Company Symbol. Published online by SinclairOil.com, http://www.sinclairoil.com/history/historys_p1.htm Accessed 27-August-2010. References Category:Dinosaurs Category:Sauropods Category:Herbivores Category:Animals Category:Fossil taxa described in 1877